Hydraulic cushioning apparatus for railway cars

ABSTRACT

A cushioning apparatus for railway cars, which apparatus includes an hydraulic cylinder fixedly positioned in a sill, a double rod piston mounted in the cylinder and connected by socketed coupling with a drawbar, and a relief valve and return flow check valve arrangement located at least at one cylinder end. A scavenging means is operably disposed adjacent the piston rod and includes an annular fitment means.

United States Patent Seay et al. [45] Mar. 7, 1972 [54] HYDRAULIC CUSHIONING 3,463,328 8/ 1969 Blake 213/43 APPARATUS FOR RAILWAY C ARS 3,216,592 ll/l965 Peterson etal. ....213/43 3,378,149 4/1968 Powell ....213/43 [72] Inventors: Orum E. Seay; Robert Q. Shelton, both of 2,816,670 12/1957 Edwards et aL M213 /43 Duncan Oke- 3,207,324 9/1965 Blake ....213/43 [73] Assignee: Halliburton Company, Duncan, Okla. 3,301,410 l/ 1967 Seay ....213/43 [22] Filed Nov 16 1970 3,483,952 l2/l969 Cardwell .,2l3/43 [2l] Appl. No.: 89,544 Primary Examner-Drayton E. Hoffman n Attorney-Bums, Doane, Swecker & Mathis Related U.S. Application Data l [62] Division of Ser. No. 732,236, May 27, 1968, Pat. No. [57] ABSTRACT 3568855' A cushioning apparatus for railway cars, which apparatus includes an hydraulic cylinder fixedly positioned in a sill, a dou- [52] U.S. Cl ble rodpiston mounted in the cylinder and co I by [5l] lm CL Blg 9/08 'B61 gg/l 6 socketed coupling with a drawbar, and a relief valve and [581 Field ofs'e'c'iifff 1213/8 43 4 67 223- 'ennn new cheek Valve anenge'nen 'eeeed e* least et ene 18S/311 313321;27/64 65 cylinder end. A scavenging means is operably disposed adjacent the piston rod and includes an annular fitment means. [56] References Clted 2 Claims 12 Drawing Figures UNITED STATES PATENTS M 1451576.71.. 6.0269 Y Strepilp efi'zt'f'. ":123/43 PATENTEUMAR 7 ma SHEET 2 UF 5 INVENTORS ORUM E. SEAY ROBERT Q. SHELTON PAIENTEDMR 1 ma y 3,647, 08a

SHEET 3 UF 5 INVENTORS GRUM E. SEAY ROBERT 0. SHELTON uml @MM5 Mu,

BY Awa/4., f fwd@- ATTORNEYS PATENTEDMAR 7 |972 3. 647. O88

' SHEET u nr 5 DRAFT END A A A v v v v HG1 H08 INVEN TORS ORUM E. SEY ROBERT 0. SHELTON www 00A-u al1-Auf 3y ugfd ATTORNEYS` HYDRAULIC CUSHIONING APPARATUS FOR RAILWAY CARS RELATED APPLICATION This application is a division of prior pending application Ser. No. 732,236, filed May 27, 1968, now U.S. Pat. No. 3,568,855 entitled Hydraulic Cushioning Apparatus for Railway Cars, and assigned by the inventors, Seay et al., to the assignee of this divisional application.

GENERAL BACKGROUND, OBJECTS, AND SUMMARY OF INVENTION The railway art is replete with devices designed to afford a cushioning action.

Such cushioning devices are particularly necessary in conjunction with the handling of freight cars. The severe shocks imposed upon freight cars in loading yards must be cushioned or absorbed if damage to goods contained in the cars is to be avoided.

In addition to being able to eectively absorb or cushion extreme buff shocks, cushioning devices must effectively control and minimize what is Voften termed train action events.

Train action events occur while a train is in motion and result v from the existence of slack in the coupling devices. Where previously extended coupling units are contracted, the train action phenomena is termed a run-in. Where contracted units are extended, the train action is tenned a runout This train action phenomena is discussed in detail in U.S. Stephenson et al. U.S. Pat. No. 3,451,561, assigned to the assignee of the present application. v

In this Stephenson application there is disclosed a highly effective concept for controlling train action events.

The efficiency of the Stephenson et al. unit notwithstanding, there remains a need for simplified cushioning devices which may be installed in existing railway cars at a nominal cost.

Therefore, this invention provides a cushioning apparatus utilizing a sill-secured cylinder and a double rod piston. In order to improve installation and servicing efficiency, relief valves and check valves at one cylinder end are located in` general alignment with a common area. A socketed coupling interconnects the piston rod and a drawbar and scavenging fitment means is associated with the piston rod.

Another aspect of the invention provides a simplified cushioning device including an impedance mechanism characterized by component modularization.

DRAWINGS In describing the invention, reference will be made to a preferred embodiment shown in the appended drawings. In the drawings:

FIG. l provides a top plan, horizontally sectioned view of a railway car sill in which is mounted a cushioning apparatus and coupling of the present invention. The cushioning apparatus is illustrated in FIG. 1 in its fully restored or neutral position;

FIG. 2 provides a partially sectioned, side elevational view ofthe FIG. l assembly;

FIG. 3 provides a partially sectioned, side elevational view of the FIG. 1 assembly in the left end portion ofthe assembly as viewed in FIG. 1;

FIG. 4 provides a top plan view of the cushioning and coupling components of the FIG. l assembly, illustrating these components at the extremity of a buff stroke;

FIG. 5 provides a reduced scale, partially sectioned, top plan view of the cushioning and coupling components of the FIG. 1 assembly illustrating the disposition of components at the end of a draft stroke of the draft key;

FIG. 6 provides a plan view of the exterior of the sidewall of the high pressure cylinder of the FIG. 1 assembly laid out flat" to illustrate the location of f'low control ports and valves;

FIG. 7 provides an enlarged, vertically sectioned, elevational view of a representative check valve mounted on the inner cylinder shown in FIG. 6, which check valve is operable to permit a return flow of fluid to the interior of the high-pressure cylinder;

FIG. 8 provides a vertically sectioned, enlarged elevational view of a control valve located in the draft end of the highpressure cylinder and operable to effectively control runout train action events;

FIG. 9 provides a reduced scale, cross-sectional view of sill, cylinder extension, yoke, draft key, and coupler components of the FIG. l assembly as viewed along section line 9-9 of FIG. l;

FIG. 10 provides a reduced scale, cross-sectional view of sill, outer cylinder, inner cylinder and piston components 'pf the FIG. 1 assembly as viewed along section line 10-10 of FIG l;

FIG. 11 provides a transverse sectional view, at reduced scale, of the yoke lugs, cylinder extension and sill as viewed along section line 1lll of FIG. l; and

FIG. l2 provides a top plan view of a coil-spring-restoring mechanism incorporated in the FIG. 1 assembly, and viewed in detached relation to this assembly.

PRINCIPAL COMPONENTS FIGS. l and 2 illustrate the principal components of the cushioning apparatus 1 'of the present invention and the positional relationships which exist between this cushioning apparatus, a coupler, and a sill of a railway car.

As shown in FIG. l, cushioning apparatus l is positioned within a conventional railway car sill 2. Apparatus l includes an outer cylinder means 3, an inner cylinder means 4, and a piston means 5.

Outer cylinder means 3, which may be deemed a low-pressure cylinder, includes a cylindrical sidewall 6. A cylinder head wall 7 is positioned at the buff end of the cylinder means 3 while another cylinder head 8 is positioned at the draft end of the sidewall 6.

Inner cylinder means 4 which comprises a high-pressure cylinder, includes a relatively thick cylindrical sidewall 9. Relatively thick wall 9 is spaced radially inwardly from the relatively thin sidewall 6 of outer cylinder means 3. The spacing between sidewalls 6 and 9 provides an annular space 10 extending coaxially of the coaxial cylinder walls 6 and 9.

The buff end of cylinder means 4 is closed by a cylinder head l1 while the draft end is closed by a cylinder head l2.

As shown in FIG. l, a unitary annular plate 13 provides each of the cylinder heads 7 and 1l. Cylinder head Il comprises a generally annular, ledgelike portion or plate I3 which is telescopingly received within the bu` or leftmost end of the sidewall 9, viewing the apparatus as shown in FIG. l. The por- .tion of plate 13 which projects radially outwardly from the plate portion ll defines the cylinder head 7, i.e. the buff end of the low-pressure cylinder means 3.

Similarly, a unitary plate 14 provides and defines each of the cylinder heads 8 and 12. Cylinder head l2 comprises an annular ledgelike plate portion which is telescopingly received within the draft end of cylinder sidewall 9. Plate portions l1 and l2 are each disposed in an interfering fit relationship with the sidewall 9.

The portion of plate 14 which projects radially outwardly from cylinder head portion l2 defines the draft cylinder head 8 for the low-pressure cylinder means 6.

Plate means 14 is mounted for axial slidable movement within cylinder wall 6. In thislconnection, a conventional O- ring-type seal l5 may be interposed between the radial periphery of the plate 14 and the inner periphery of the sidewall 6 for sealing purposes.

With this arrangement, the cylinder heads 8 and l2 are each mounted within the cylinder wall 6 and are axially movable toward the plate 13. The movability of these cylinder head walls 8 and l2, in relation to the plate 13 is limited by the high pressure and relatively thick sidewall 9 which is interposed axially between the plates 13 and 14. Thus, in terrning the cylinder heads 8 and 12 movable, the term movable is being used in a sense to indicate that the plate 14 is not fixedly connected with the wall 6, but rather, as is now apparent, is movable axially of wall 6 in response to buff shock-induced, axial contraction of wall 9.

Piston means includes a piston 16 disposed for telescoping and axially slidable movement within and relative to the high pressure cylinder wall 9. A main piston rod 17 passes coaxially through the draft end plate 14 by way of a central aperture 18.

An auxiliary piston rod 19 extends coaxially of the piston rod 17, away from the piston 16 and rod 17, and coaxially through the end plate 13 by way of a plate aperture 20. The cross-sectional area of piston rods l7 and 19 are identical.

' Movement of end wall 14 away from wall 13 is airmatively prevented by a cylindrical extension 2l. Cylindrical extension 21 is fixedly connected with sidewall 6 and extends coaxially away from wall 6 and end plate 14. Cylindrical extension 21 provides an annular ledge 22 which abuttingly engages the periphery of the plate 14 so as to prevent movement of the plate 14 away from the plate 13.

Cylindrical extension 21 engages, and is fixedly connected with, an end plate means 23. End plate means 23 has a rectangular configuration of the interior 24 of the sill 2. End plate 23 is receivable within the interior space in substantially conforming relation with the sill cross section and thus functions to align and stabilize the assembly l.

As will be appreciated, reinforcing webs (not shown) may extend along cylindrical extension 2l between the sidewall 6 and the end plate 23 for reinforcing and strengthening purposes.

Conventionally, interior passage 24 of sill 2 will have a square cross section. Thus,'as shown in FlG. l0, the outer diameter of wall 6 may be substantially the same as the width and height of the stabilizing end plate 23. With this dimensional relationship, the cylinder 6 will engage the sidewalls of the interior of the sill 2 so as to stabilize and align the cylinder 6 in coaxial alignment with the central longitudinal axis of sill 2.

Anchoring of the assembly l within the sill 2 is effected by a series of anchoring abutments. Two such bracketlike abutments 25 and 26, shown schematically in FIGS. l and 2, provide abutment means engaging opposite, horizontally spaced, sides of the end plate 13 so as to prevent buff movement of this plate.

A pair of ledgelike vertically extending stops or abutments 27 and 28 project laterally inwardly from the sill sides so as to abuttingly engage the forward edge of the plate 23. Thus, abutment stops 27 and 28 serve to prevent buff movement of the plate 23, cylinder extension 21, cylinder wall 6 and end plate 13.

Abutments 25, 26, 27 and 28 may be provided by a draft end sill casting of the general type manufactured by Scullen Steel Company of St. Louis, Missouri, and illustrated on page 675 of the Car and Locomotive Encyclopedia (Simmons- Boardman 1966).

A second cylindrical extension 29 is connected with plate 23 and projects coaxially of plate 23 away from cylindrical extension 2l. Extension 29 contains a pair of horizontally displaced slots 30 and 31. These slots 30 and 31 are horizontally aligned respectively with conventional sill slots 32 and 33. As illustrated, extension slots 30 and 31 intersect the free extremity 34 of cylindrical extension 29.

A yoke 35 is slidably supported within a common cylindrical wall 36 defined by axially contiguous portions of the extension 21, alignment plate 23, and extension 29. Thus, yoke 35 has a substantially circular cross section so as to enable it to be telescopingly and slidably received within the guiding and constraining wall 36. Sliding movement of the yoke 3S along the wall 36 may be facilitated by a bushing 40.

Yoke 35 includes a pair of horizontally spaced yoke slots 41 and 42. Slot 4l is aligned horizontally with slots 30 and 32 while yoke slot 42 is aligned horizontally with slots 3l and 33. v

Viewing the apparatus as shown in FIG. 1, the rightmost end of slots 4l and 42 are closed by longitudinally extending mirror image related, and horizontally spaced lugs 43a and 43h.

ln this connection, it will be appreciated that yoke portion 44 which provides slots 4l and 42, is substantially cylindrical in character. Yoke portion 44 is disposed in coaxial relationship with the rim 43 and the piston means 5.

Sliding movement of yoke 43 may be stabilized by a pair of lugs 45 and 46. Lugs 45 and 46 project radially outwardly from rim 43 and are disposed in horizontal alignment, respectively, with extension slots 30 and 31. Thus, during buff movement, the lugs 45 and 46 will slidably enter the open-ended slots 30 and 3l for yoke stabilization and guiding purposes.

Piston rod 17 is connected to yoke 35 by a conventional spherical bearing 47. Mounting plate means 48 and 49, each anchored to yoke 35 by known fastening means, not shown, provide spherical bearing surfaces cooperating with the spherical bearing 47 of rod 17. These plate means serve to fixedly anchor the spherical bearing 47 in a central pocket portion 50 of yoke 3S disposed in the left end of yoke 35, viewing the apparatus as shown in FIG. l.

As illustrated, shaft 17 enters yoke 35 through a yoke aperturel 5l. With the spherical bearing arrangement being well i known in the railway-coupling art, its structural details need not be discussed. Suice it to say that this bearing arrangement provides a mechanism for fixedly connecting the piston rod 17 to the yoke 35 so as 'to prevent axial movement between these components but permit proper accommodation of forces acting nonaxially on the yoke 35.

A conventional coupler or draw bar 52 is interconnected with the sill 2 and yoke 35 by a conventional draft key 53. Draft key 53 has a substantially rectangular cross section in a direction extending longitudinally of sill 2. Key S3 is provided with a longitudinally exten;ing slot 54-embracing key 53.

As will be appreciated from the foregoing discussion, head and slot connecting means 47, 48, 49, 50 and 5l, provides a stress-relieving coupling between piston rod means 17 and the drawbar means 52. The interior of yoke 35 provides a socket within which the head end 47 of the piston rod 17 is received.

Key 53 passes consecu,ively through the sill slot 33, the extension slot 31, the yoke slot 34, the drawbar slot 54, the yoke slot 4l, the extension slot 30 and the sill slot 32.

As shown, key 53 is capable of undergoing longitudinal sliding movement between the ;raft extremity 54a of slot S4 and the buff 54h of this slot.

Similarly, key 53 is operable to undergo longitudinal sliding movement between the buff extremities 41a and 42a of slots 4l and 42 and the draft extremities 41b and 42b of these slots.

Additionally, the key 53 is operable to undergo longitudinal sliding movement between the buff extremities 32a and 33a of sill slots 32 and 33, respectively, and the draft extremities 32h and 33b of these sill slots.

FIGS. l and 2 illustrate the piston 16 disposed in its fully restored or neutral position within the cylinder wall 9. This positioning of the piston 16, which occurs in the absence of extraneous coupler forces acting on the piston rod 17, results from a restoring mechanism 55.

As shown in FIGS. 2, 9 and l2, restoring mechanism 5S comprises rearward and forward mounting bracket means 56a and 56b, respectively. Bracket 56a is attached to an under portion 57a of sill 2, while bracket means 56a is attached to an under portion 57a of sill 2, while bracket means 56b is attached to an under portion 57b of the railway car sill.

A tongue 58 projects downwardly from the yoke 35. Tongue 58 is fixedly connected with a horizontally extending connecting means 59.

A pair of horizontally spaced and longitudinally extending sleeve or cylinderlike rods 60a and 60b are fixedly supported at their extremities by brackets 56a and 56b. Threaded rods 60e and 60d pass through sleeves 60a and 60b and connect these units to brackets 56a and 56h. A coil spring 61a is mounted on rod 60a with its leftmost extremity anchored by the bracket means 56a. Another coil 6lb is anchored on rod means 60b with its leftmost end also engaged by the fixed bracket means 56a.

Tongue 58 fixedly engages an annular recessed portion or groove 59a of connecting means 59. This mounting groove 59a is formed on a fitment 59h which is fixedly mounted on a rod 59C. A coil spring 59d is telescopingly mounted on rod 59e. A rod-carried abutment 59e engages a rightrnost extremity of the coil spring 59d. An annular flangelike abutment 59f engages the leftmost end of spring 59d. Flange 59f is formed, as shown in FIG. l2, on a cylindrical fitment 59g which is connected to and projects leftward from a plate 59h. Plate 59h is slidably mounted on rods 60a and 60h. Plate 59h abuttingly engages the rightmost ends of springs 61a and 61b as shown in FIG. l2. Fitment 59g is axially apertured so as to accommodate axial sliding movement of the rod 59e.

By reference to FIGS. 2, 9 and l2, it will be appreciated that tongue 58 projects downwardly through a longitudinally extending slot 62 formed in the base of extension 29 and also downwardly through an opening 63 in the base of sill 2. Opening 63 and slot 62 accommodate buff-and-restoring draft movement of the tongue 58.

During bumovement, the tongue 58 carries the fitment 59a and to the left, viewing the apparatus as shown in FIGS. 2 and 12. This leftward movement tends to cause the plate 59h to compress the springs 61a and 61b as the plate moves slidably to the left over sleevelike rods 60a and 60b. This leftward movement of the tongue 58 and fitment 59a also tends to cause the rod 59e to move telescopingly through the axially apertured fitment 59g so as to cause the rod flange 59e to compress the spring 59d.

Thus, the springs 59d, 61a and 61b are all available to contribute to the resilient restoring of the tongue 58 to its neutral position. This restoring, of course, will result from the tendency of the spring 59d to restore the rod 59C to the position shown in FIG. 12, along with the tendency for the springs 61a and 61h to restore the plate 59h to its position of abutting engagement in relation to the mounting flange means 56b.

As will be appreciated, the abutment means 56a and the plate 59h provide abutment means operable to tend to cornpress the coil springs 61a and 61b in response to buff movement of the coupler 52. The energy stored in springs 61a and 6lb, through this compression, tends to restore the coupler 52 to the extremity of draft movement shown in FIG. l.

This restoring action is augmented by the additional or auxiliary coil spring 59d. Abutments 59e and 59f, in essence, provide abutment means interposed between the coupler 52 and the rightmost end of the springs 61a and 6lb. This second abutment means tends to induce compression of the additional spring 59d when relative movement between tongue 58 and coil springs 61a and 61b occurs, i.e., when relative buff movement between the coupler 52 and this pair of horizontally spaced coil springs occurs. This compression of spring 59d provides an auxiliary restoring force tending to move the coupler 52 back to the extremity of its draft travel as shown in FIG. l.

At this point, it will be recognized that the extremity of the draft position of coupler 52 is defined by concurrent engagement between the key 53 and sill slots 32b and 33h, between the key 53 and coupler slot end 54a, and between coupler face 113 and piston rod plate 48.

lt is significant to here note that this position of neutrality completely negates the common notion that a restoring mechanism must provide a neutral position accommodating some draft movement.

IMPEDANCE SYSTEM FIGS. l, 2, 6, 7 and 8 illustrate structural details of the impedance system which serves to control train action events and effectively absorb extreme impact forces acting upon the coupler 52.

The impedance mechanism includes a series 64 of longitudinally displaced ports formed in high-pressure cylinder wall 9.

At this point, it should be noted that in FIGS. 1 through 5, the ports in series 64 are illustrated in a schematic format only, for ease of overall comprehension. In fact, as shown in FIG. 6, these ports are staged about the circumference of wall 9 and are spaced longitudinally of the axis of cylinder wall 9 in an exponential fashion, with the port spacing decreasing exponentially in a direction extending away from the draft end of' the cylinder means 4 toward the buff end, i.e., the cylinder end closed by cylinder head yl1. This exponential spacing is described in detail inthe Seay U.S. Pat. No. 3,301,410. While exponential spacing is desirable, it is possible the exponential spacing may be modified or that additional nonexponentially spaced ports may be provided, depending upon anticipated operating conditions.

Thus', as the piston 16 undergoes buff movement from the neutral position shown in FIG. l, hydraulic fluid, which fills high-pressure zone 65, will be expelled from the zone 65 radially outwardly through the port series 64, and into the interior 10 of the low-pressure cylinder means 3. This fluid expelled from zone 65, in response to buff movement of the piston 16, is returned to the draft side 65a of the interior space 65 by three relatively high-capacity check valves 66, 67 and 68.

Conversely, during draft movement of the piston 16, away from the full buff` position of this piston shown in FIG. 4, fluid is expelled from high-pressure zone 65a through the port series 64 into the low-pressure zone 10. This fluid from the lowpressure zone l0 returns to the buff end 65b of the high-pressure cylinder zone 65 by way of a fourth check valve 69.

From a structural standpoint, each of the check valves 66, 67, 68 and 69 is identical such that it is appropriate to describe structural details of only one representative valve 69.

As shown in FIG. 7, valve 69 includes a cylindrical body portion 70, connected to the exterior of cylinder wall 9. This body portion includes a male-threaded coupling portion 71 which is threadably connected with a female-threaded aperture 72 in cylinder wall 9. A cylindrical valve member 73 is mounted for telescoping movement within body member 70. A coil spring 74 biases valve 73 radially outwardly to the closed valve position shown in FIG. 7. This biasing is effected by having one end 74a of coil spring 74 disposed in abutting engagement with an annular, valve body ledge 7S, with the other, outermost end 74b of spring 74 engaging an annular valve flange 76. In the closed valve position a plurality of ports 77, projecting radially through a cylindrical valve wall 78, are isolated from the high-pressure zone 65. This isolation is effected by having a closed plate 79 at the inner end of valve 73 valvingly and substantially sealingly engage a seat 80 formed in valve body 70.

With this valve structure, fluid pressure within the zone 65 will tend to close the valve. Pressure in the zones 10, which exceeds that in the zone 65, will overcome the biasing influence of the valve spring 74 and move the valve member 73 inwardly to an open valve condition.

The three valves 66, 67 and 68 at the draft end of the cylinder wall 9 provide the necessary high flow capacity to return flow to the cylinder zone 65a during bu' movement of' the piston 16. Indeed, the total capacity of the ports 77 of each of the valves 66, 67 and 68 may substantially exceed the total flow capacity of the ports 77 of the valve 69 so as to more effectively accommodate the buff return flow. As will be appreciated, with the draft shock forces being normally substantially less than buff shock forces, the lower capacity of the single valve unit 69 will provide a suicient return flow capacity to enable fluid to be restored to the buff zone 65h in response to draft movement of the piston 16.

Effective control over runout-type train action events is provided by a control valve 8l mounted in the draft end of the cylinder wall 9 as shown schematically in FIG. 6. Valve 81 is of the control valve type described in detail in the aforesaid Stephenson et al. U.S. Pat. No. 3,451,561.

As is shown in FIG. 6, the plurality of relatively high-capacity check valve means 66, 67 and 68 and the relief valve means 81 are located in general alignment with a common plane extending perpendicular to the axis of reciprocation of piston means 16.

threadedly engaged with a female-threaded aperture 84 formed in wall 9.

As will be here appreciated, the radial width of the annular space l is sufficient to accommodate this mounting of the valve 31, as well as the previously described and essentially similar mountings of the return valves 66, 67, 68 and 69, and allow for flow through these valves between the zones and 65.

Valve 8l includes cylindrical valve member 85 mounted for telescoping axial movement in a valve body aperture 86. A coil spring 86 biases the valve member 85 radially inwardly. This biasing is effected by having the innermost end 87a of spring 87 engage a flange 88 projecting radially outwardly from the valve member 85, while an outermost end 87b of spring 87 engages a flange 89 projecting radially inwardly from cylindrical valve body 82.

With this biasing arrangement, one or more radially extending ports 90 formed in valve member 85 are disposed inwardly of cylinder wall 9 so as to be in fluid communication with the zone 65. The innermost extremity of the valve member 85 is closed by a valve head plate portion 91, as schematically shown.

With the valve member 85 biased to the normally open valve position shown in FIG. 8, fluid may flow out of the draft zone 65a and into the lower pressure zone 10 in response to draft movement of the piston 16. Thus, in railway yards, if car coupling has been effected so as to induce some buff movement of the piston 16, the normally open condition of the valve 8l will provide for a relatively rapid restoration of the piston 16 to the neutral position illustrated in FIG. l. However, with a train in motion, and with runout train action tending to impose relatively higher draft movement velocities on the piston 16, the fluid flowing through the port means 90 will be moving at such a velocity as to create a pressure drop across the wall 91 operable to move the valve member 85 outwardly to a closed valve position. This closed valve position will result by retracting the ports 90 into the wall aperture 86, and by moving the valve head 92 into substantially valve closing engagement with the wall portion 93 of the valve body 82. Once valve 81 closes in response to such runout action, increased resistance to an outflow of fluid from zone 65a results. This increased resistance to an outflow of fluid flow effectively impedes the draft movement of the piston 16 so as to reduce the severity and extent of the runout event.

FLUID-SCAVENGING AND RETENTION SYSTEM A significant facet of the invention resides in a unique scavenging and fluid-retention system which effectively eliminates the need for high-precision seal structures.

As shown in FIGS. 1, 2 and 3, the auxiliary piston rod 19 is supported by a bushing 94. Bushing 94 is mounted in the aperture and interposed radially between the edge of this aperture in plate 13 and the auxiliary piston rod 19. The bushing 94 provides effective stabilization and guiding for the auxiliary piston rod 19 but may permit some axial leakage between the bushing 94 and the shaft 19.

Hydraulic fluid which may have leaked between the bushing 94 and the shaft 19 will enter a fluid reservoir 95 defined by a vertically elongate housing wall 96. Housing wall 96, which is operable to telescopingly receive piston rod 19 during its buff movement, may be secured by threaded fastening means 96a to end plate 13 so as to be located externally of the unit cylinder means and enclose the end of auxiliary piston rod 19 which projects beyond wall 13 and away from the high-pressure zone 65. Thus, wall 96 serves to protect the reciprocating or auxiliary piston rod 19 and also serves to retain hydraulic fluid which has leaked out of the zone 65b. This fluid is returned to the low-pressure reservoir zone l0 by passage means 97 formed in the lower end of the plate 13, as schematically shown in FIG. 3.

A seal assembly 98 fabricated of conventional sealing elements is interposed radially between the periphery of the aperture 18 of plate 14 and the outer periphery of the main piston rod 17. Fluid that may tend to leak along the interface of the seal means 98 and the shaft 17 is returned to low-pressure reservoir 10 by way of the scavenging passage means 99 shown schematically in FIG. 3.

Passage means 99 communicates with the interface of the seal means 18 and shaft 17 by way of an annular fitment 100. This fitment includes an annular groove 101 adjacent the shaft 17, an annular groove 103 communicating with the scavenging passage means 99, and radial ports 104 which provide communication between the grooves 101 and 103.

In this connection, it will be understood that the cavities 65 and 10 and the reservoir 95 will be substantially filled with hydraulic fluid which serves to impede and control the movement of the piston 16. This hydraulic fluid will completely fill the space 65 and will occupy the void space of reservoir 95 and the void space in low-pressure zone 10 so as to provide a fluid head operable to maintain complete filling of the highpressure zone 65. However, in zones and 10, enough void space must be left to accommodate reciprocating movement of piston rod 19 in space 95.

DIMENSIONAL CRITERIA With key 53 engaging coupler slot end 54a, a longitudinal gap 105 exists between coupler slot end 54b and key 53.

With key 53 engaged with sill slot ends 32h and 33 b, and with yoke 35 disposed at its fully restored position, a longitudinal gap 106 will exist between the key 53 and the yoke slot ends 41b and 42b.

The axial extent of the gap 105 slightly exceeds the longitudinal extent of the gap 106.

The longitudinal gap 107 between the leftmost end 108 of yoke 35 and the rightmost abutment defining end 109 of plate 14 determines the extent of draft travel of the yoke 35.

The increment 107 is slightly shorter than the longitudinal increment 107a existing between the leftmost side 110 of the piston 16 and the rightmost side 1.11 of cylinder zone 65, as defined by the bushing 94 and the cylinder head ll.

The longitudinal length 112 of the coupler portion extendin'g between slot end 54a and the leftmost extremity l 13 of the coupler 52 is such as to enable the plate 48 to abuttingly engage the coupler bar face 113, with the yoke 35 fully restored and the key 53 engaged with the sill slot ends 32h and 33b. ln other words,. the longitudinal extent of this portion of the coupling bar enables the yoke 35 to be fully restored without engagement between the key 53 and the sill slots and coupler slot preventing such full restoration.

The longitudinal gap 114 between key 53 and sill slot ends 32a and 33a (with key engaging slot ends 32b and 33h), augmented by the length of gap 106, yields an increment which is slightly less than the length of increment 107. This allows for a two-stage transfer of buf shock to sill 2, in a manner to be now described.

MODE OF OPERATION OF UNIT The operation of the cushioning device 1 will be described, consecutively, from a condition of neutrality, through a full buff condition, and finally back to a condition of full restoration or neutrality.

Commencing with the neutral or fully restored condition of the apparatus shown in F 1G. 1, it will be seen that the yoke 35, acting through the plate 48 is in engagement with the coupler end 113. As buff force is imposed on the coupler 52, the coupler end l 13, acting on the plate 48, presses the yoke 35 to the left. As this buff movement continues, under the full control of the hydraulic fluid within the zone 65h, the key 53 will be brought into engagement with the sill slot ends 32a and 33a. With the key 53 thus engaging these sill slot ends, the other or rightmost end of the key 53 will abuttingly engage the yoke slot ends 41h and 42b. This concurrent engagement between the yoke and sill slot ends and the key 53 will occur slightly before the yoke face 108 abuttingly engages the cylinder defined abutment 109, because of the previously described relations between increments 114, 106 and 107. Thus, the elasticity of the sill, key and yoke will provide some initial absorption of buff forces, while the yoke 35 continues limited buff movemerit equal to the difference between the increments or gaps 105 and 106. This difference in increments is sufficient to enable the continued buffed movement of the yoke 35 to bring the faces 108 and 109 into abutting engagement. When this abutting engagement occurs, shock forces will be transmitted, in a second phase, through the plate 14 and heavy cylinder wall 9 to the end plate 13. This shock force transmitted to the plate 14 will be transmitted to the sill 2 through the abutmentdefining brackets 25 and 26.

Thus, it will be appreciated that mechanical buff force is absorbed in two stages. The first stage of mechanical shock absorption occurred at the point where the yoke slot ends 41b and 42b and the sill slot ends 32a and 33a simultaneously engaged the key 53. The second, and subsequent, stage of mechanical shock absorption occurred at the point where the face 108 abuttingly engaged the cylinder face 109. At this point of second shock absorption, illustrated in FIG. 4, it is significant to note that mechanical shock is dissipated or transmitted through the unit 1 to the sill 2 without passing through the relatively thin-walled, cylinder sidewall 6. In this manner, damage to the thin-walled cylinder means 3 is effectively avoided.

Restoration of the piston 16 from the full buff condition shown in FIG. 4 to the control position shown'in FIG. 1, is effected by springs of the restoring mechanism 55.

When faces 108 and 109 abut, some space remains in zone 65h, as shown in FIG. 4. This insures that, in the full buff position of piston 16, excessive fluid pressure is not developed. During the restoring or draft movement of the piston 16, influenced either by the mechanism 55 or a draft force acting on the coupler 52, the yoke 35 will move to the right, viewing the apparatus as shown in FIG. 1.

Near the end of this draft movement, the key 53 will be brought into abutting engagement with the sill slot ends 32b and 33h.

Where the draft force of coupler 52 exceeds the restoring force of unit 55, this abutting engagement between the key and the sill slot ends take place prior to the termination of the restoring movement of the piston 16 and the yoke 35. The previously noted gaps 106 and 105 will enable the yoke 35 to continue its restoring movement for an increment equal to the gap 106. This continued movement of the yoke 35, which will be effected by the restoring mechanism 55, will close the gap 106 between the coupler 52 and the yoke 35, i.e., bring the yoke face 48 into abutting engagement with the coupler end l 13.

As shown in FIG. 5, with draft forces acting on the coupler 52, the gap 106 will exist longitudinally between the face 113 and the plate 48 at the point where the key 53 has engaged the slot ends 32h and 33b, assuming, of course,.as earlier noted, that draft force on coupler 52, rather than the restoring spring force of unit 55 is governing restoration.

Where the restoring force of unit 55 governs, gap 106 between face 113 and plate 48 will have been closed prior to the engagement of key 53 with slot ends 32b and 33h. However, even under this mode of restoration, the unit parts, at full restoration, will assume the disposition shown in FIG. 1.

lt will thus be appreciated that train action or runout events as determined by the sliding movement of the key 53 in the sill slots 32 and 33 are limited to the gap 114 schematically shown in FIG. 1. This gap 114 is less than the increment of buff movement of the coupler 52 under the continuous control of the fluid in the reservoir 65 of the impedance mechanism. As will be appreciated the difference between the key slot-controlled increment 114 and the total increment 107 of controlled buff movement results from the gaps and 106, i.e., lost-motion connections between the coupler and the key as well as between the yoke and the key.

SUMMARY OF MAJOR ADVANTAGES AND SCOPE OF INVENTION The overall combination of the sill-mounted cylinder, the double rod piston, and the stress-relieving coupling between the rod and a drawbar provides a uniquely easy to install drop-in type assembly. This assembly requires minimal sill modification, yet is rugged in its operating characteristics.

The arranging of the check valves and relief valves in general alignment with a common plane, at least at one end of the cylinder, as shown, for example, in FIG. 6, provides an installation which is relatively easy and convenient to fabricate and service.

A principal advantage of the invention resides in the provision of an e`ective system for transmitting mechanical shock through a cushioning device so as to transmit force through a heavy-walled cylinder and avoid the potentially injurious transmission of force through a thin-walled cylinder whichen-` circles the thicker cylinder wall.

The two-stage force transfer, in buff action, tends to minimize mechanical damage `during the handling of high buff shocks.

Another principal advantage of the invention resides in a lost-motion arrangement which affords an extent of hydraulically controlled buff movement greater than that which would result from the normal sliding movement of a draft key through sill slots. Thus, the shock-absorbing advantages of a relatively long buff stroke are obtained, while maintaining key movement determined, train action phenomena at a somewhat lower level.

Since the severity of train action events increases with the extent of travel of the draft key in the sill slots, maintaining the key travel .at the lowest possible level tends to reduce the severity of train action events.

The use of the auxiliary piston rod in conjunction with the main piston-rod avoids the necessity of compensating for the entry of the main piston rod into the fluid reservoir 65. Thus,

resilient accumulators, etc., previously often incorporated in cushioning devices may be entirely eliminated.

It is also significant to note that the restoring me.hanism restores the coupler'to a position where no draft movement is possible. This restoration substantially simplifies overall cushioning unit structure, in direct defiance of what was previously thought to be the necessary accommodation of draft movement from the neutral position of an hydraulic cushioning unit.

The unique structure and disposition of the three coil springsof the-restoring unit provides, in an axially compact and .vertically compact package, a restoring mechanism of optimumrestoring capability.

The scavengngand fluid-retention system of the unit enables the avoidance of high-precision seals so as to maintain fabrication cost` at a relatively low level.

The check valve flow control system, aswell as the train action control valve, providea modular concept for controlling `fiuid flow in Aswillbe appreciated, the overallfunit is characterized by .extremevsti'uctural simplicity ,gandis-readily incorporable in conventional,railwaylcar sills.v Little orv no modification of such sills is requiredto effect the` installation of the cushioning unit. g ln describing and claimingthe invention, reference has been Vmacle `to vvarious key-and-slot structures. Where this terminology is employed itwill be understood that it is intended to contemplateand embrace the obvious reversal of parts, the

.use ofpinsin lieuof fiat platelikekeys, etc. lt will also be un- In describing the invention, reference has been made to a preferred embodiment. However, those skilled in the railwaycushioning art and familiar with the disclosure of this invention may well recognize additions, deletions, substitutions, or other modifications which would fall within the purview of this invention as set forth in the appended claims.

What is claimed is: l. A railway-cushioning apparatus comprising: cylinder means having wall means including sidewall means, first end wall means, and second end wall means, said first and second end wall means being connected with and spaced longitudinally of said sidewall means; mounting means operable to secure said cylinder means in generally fixed position within a railway car sill; piston means slidably disposed within said cylinder means and including, piston body means telescopingly mounted within said sidewall means of said cylinder means, and piston rod means telescopingly projecting through each of said first and second end wall means of said cylinder means; interior impedance zone means located within said cylinder means, said impedance zone means containing liquid, and being operable to impede movement of` said piston body means relative to said sidewall means of said cylinder means, with said piston body means in combination with said cylinder sidewall means defining buH and draft ends of said impedance zone means located on longitudinally opposite sides of said telescopingly mounted piston body means; generally annular return flow passage means comprising a continuous chamber surrounding said first and second end wall means and sidewall means of said cylinder means by generally encircling at least said sidewall means and at least portions of said first and second end wall means of said cylinder means and operable to receive fluid expelled from said impedance zone means in response to movement of said piston body means relative to said cylinder sidewall means; generally fluidtight housing means comprising generally mutually sealed side and end wall portions operable to house said cylinder means and return flow passage means,`

with the chamber of said return flow passage means being disposed between said housing means and said cylinder means; socketed coupling means operable to interconnect said piston rod means and a drawbar of a railway car; said socketed coupling means including enlarged head means carried by said piston rod means, yoke means operable to be connected with said drawbar,

and socket means defined by said yoke means and operable to support said enlarged head means in socketed relation with said yoke means; port means in said cylinder means disposed at said buff and draft ends of said cylinder means and providing communication between said buff and draft ends of said interior impedance zone means of said cylinder means and said continuous chamber and operable to impede a flow of fluid out of said impedance zone means in response to buff and draft force induced movement of said piston body means relative to said cylinder sidewall means;

relatively high-capacity check valve means carried by said cylinder means and operable to permit a flow of fluid from said continuous chamber into at least one of said buff and draft ends of said impedance zone means of said cylinder means; and

relief valve means operable to relieve pressure in said at least one of said buff and draft ends of said impedance zone means and carried by said cylinder means; said relief valve means and said relatively high-capacity check valve means each including passage means defining a continuation of said at least one of said buff and draft ends of interior impedance zone means;

scavenging means including generally annular fitment means telescopingly receiving a portion of said piston rod means,

generally annular scavenging passage means carried by said fitment means, generally encircling said piston rod means, and operable to receive fluid passing between said fitment means and said portion of said piston'rod means,

first transverse passage means extending through said fitment means generally outwardly of an axis of reciprocation of said piston rod means and communicating with said generally annular scavenging passage means. and

second passage means defining a continuation of said return flow passage means, and providing communication between said first transverse passage means and a portion of said return flow passage means generally adjacent one of said first and second end wall means; and

said relief valve means and said check valve means each including valve seat means and valve means valvingly cooperable with said valve seat means, with each said valve seat means and valve means being contained inside said cylinder means and housed within a continuation of said impedance zone means which is contained within body means of said wall means of said cylinder means.

2. A railway-cushioning apparatus as described in claim l wherein:

said check valve means includes a plurality of relatively high-capacity check valve means, each independently operable to permit a flow of fluid between said return flow passage means and said impedance zone means; and said apparatus further includes generally rigid piston-rodshielding means located externally of said cylinder means and operable to telescopingly receive a portion of said piston rod means in response to buff force induced movement of said piston means.

t k i 

1. A railway-cushioning apparatus comprising: cylinder means having wall means including sidewall means, first end wall means, and second end wall means, said first and second end wall means being connected with and spaced longitudinally of said sidewall means; mounting means operable to secure said cylinder means in generally fixed position within a railway car sill; piston means slidably disposed within said cylinder means and including, piston body means telescopingly mounted within said sidewall means of said cylinder means, and piston rod means telescopingly projecting through each of said first and second end wall means of said cylinder means; interior impedance zone means located within said cylinder means, said impedance zone means containing liquid, and being operable to impede movement of said piston body means relative to said sidewall means of said cylinder means, with said piston body means in combination with said cylinder sidewall means defining buff and draft ends of said impedance zone means located on longitudinally opposite sides of said telescOpingly mounted piston body means; generally annular return flow passage means comprising a continuous chamber surrounding said first and second end wall means and sidewall means of said cylinder means by generally encircling at least said sidewall means and at least portions of said first and second end wall means of said cylinder means and operable to receive fluid expelled from said impedance zone means in response to movement of said piston body means relative to said cylinder sidewall means; generally fluidtight housing means comprising generally mutually sealed side and end wall portions operable to house said cylinder means and return flow passage means, with the chamber of said return flow passage means being disposed between said housing means and said cylinder means; socketed coupling means operable to interconnect said piston rod means and a drawbar of a railway car; said socketed coupling means including enlarged head means carried by said piston rod means, yoke means operable to be connected with said drawbar, and socket means defined by said yoke means and operable to support said enlarged head means in socketed relation with said yoke means; port means in said cylinder means disposed at said buff and draft ends of said cylinder means and providing communication between said buff and draft ends of said interior impedance zone means of said cylinder means and said continuous chamber and operable to impede a flow of fluid out of said impedance zone means in response to buff and draft force induced movement of said piston body means relative to said cylinder sidewall means; relatively high-capacity check valve means carried by said cylinder means and operable to permit a flow of fluid from said continuous chamber into at least one of said buff and draft ends of said impedance zone means of said cylinder means; and relief valve means operable to relieve pressure in said at least one of said buff and draft ends of said impedance zone means and carried by said cylinder means; said relief valve means and said relatively high-capacity check valve means each including passage means defining a continuation of said at least one of said buff and draft ends of interior impedance zone means; scavenging means including generally annular fitment means telescopingly receiving a portion of said piston rod means, generally annular scavenging passage means carried by said fitment means, generally encircling said piston rod means, and operable to receive fluid passing between said fitment means and said portion of said piston rod means, first transverse passage means extending through said fitment means generally outwardly of an axis of reciprocation of said piston rod means and communicating with said generally annular scavenging passage means, and second passage means defining a continuation of said return flow passage means, and providing communication between said first transverse passage means and a portion of said return flow passage means generally adjacent one of said first and second end wall means; and said relief valve means and said check valve means each including valve seat means and valve means valvingly cooperable with said valve seat means, with each said valve seat means and valve means being contained inside said cylinder means and housed within a continuation of said impedance zone means which is contained within body means of said wall means of said cylinder means.
 2. A railway-cushioning apparatus as described in claim 1 wherein: said check valve means includes a plurality of relatively high-capacity check valve means, each independently operable to permit a flow of fluid between said return flow passage means and said impedance zone means; and said apparatus further includes generally rigid piston-rod-shielding means located externally of said cylinder means and operable to telescopingly receive a portion of said piston rod means in response to buff forCe induced movement of said piston means. 